The present invention relates to a clutch cover assembly, particularly to a clutch cover assembly with a mechanism for keeping a pressing load constant by compensating for the wear on the friction members.
A clutch cover assembly is, generally, fixed to a flywheel of the engine and presses friction members of the clutch disc assembly against the flywheel in order to transmit the power of the engine to the transmission. Excessive wear on the friction members shortens the lives of the clutch disc assembly and the clutch disc assembly. It is possible to lengthen life of the clutch disc assembly by increasing effective thickness of friction members. For example, by attaching facings to the cushioning plate without using rivets.
The clutch cover assembly disclosed in Japanese Patent Laying-Open No. 27092/1998 maintains the pressing load of the diaphragm spring at its initial value as facings wear. This clutch cover assembly is shown in FIG. 10 and has a pressure plate 151 formed with an annular groove 152 in which a diaphragm spring posture maintenance mechanism 153 is arranged. The mechanism 153 comprises both an outer fulcrum ring 155 and an inner fulcrum ring 156 against which the outer periphery of the diaphragm spring 154 presses, slide keys 157 and 158 located between the fulcrum rings 155 and 156, and the grooved pressure plate. Both slide keys 157 and 158 are formed with an inclined surface such that axial height deceases radially outward. The fulcrum rings 155 and 156 are formed with inclined surfaces conforming to the inclined surfaces of the slide keys 157 and 58. The slide keys 157 and 158 are urged radially outward by springs 159 and 160, respectively.
The inner fulcrum ring 156 is moved toward the diaphragm spring 154 by the spring 160 and the slide keys 158 as facings 161 wear. Upon release, both fulcrums 155 and 156 move in concert, thus the posture of the diaphragm spring 154 and the pressing load of the diaphragm spring 154 is maintained at the initial value.
In the above-mentioned structure, it is necessary to form the groove 152 in the lateral surface of the pressure plate 151 to contain the spring posture maintenance mechanism 153. The groove 152 is difficult to fashion, deviation thus complicating accurate and correspondent movement of the fulcrum rings 155 and 156, affecting amount of wear on the facings 161. Therefore, design requirements make it difficult to maintain the initial pressing load of the diaphragm spring 154.
The above-mentioned structure is further affected when the engine rotation speed rises, applying centrifugal force to the slide keys 157 and 158, thus making the slide keys move radially outward. In this case, even though the facings 161 are not worn, the slide keys 157 and 158 move so as to move the fulcrum rings 155 and 156 axially. As a result, it is impossible to maintain the posture of the initial pressing load of the diaphragm spring 154.
It is an object of the present invention to maintain the initial pressing load of the pressing member by compensating for displacement due to wear on friction members.
A clutch cover assembly according to an aspect of the present invention for urging friction members connected to an output member against an input rotation member and for releasing urging on the friction members. The clutch cover assembly comprises a clutch cover, a pressure plate, a pressing member, a support mechanism, and a movement regulation mechanism. The clutch cover is fixed to the input rotation member. The pressure plate is located within the clutch cover for pressing the friction members. The pressing member presses the pressure plate toward the friction members. The support mechanism, movable toward the friction members, supports the pressing member. The movement regulation mechanism moves the support mechanism toward the friction members according to the wear of the friction members.
In this clutch cover assembly, the pressing member is supported by the support mechanism and presses the pressure plate toward the friction members so that the friction members are sandwiched between the input rotation member and the pressure plate, whereby the power is transmitted from the input rotation member to the output member.
When the friction members are worn, the movement regulation mechanism moves the support mechanism toward the friction members to that the initial pressing posture and the initial pressing load of the pressing members are maintained. It is possible to maintain the initial pressing load correctly since the pressing posture of the pressing member is maintained by moving the pressing member toward the friction members. It is precise and of simple structure.
The foregoing and other objects and advantages of the present invention will become more apparent from the following detailed description, with reference to the accompanying drawings.